The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The instant disclosure generally relates to geological modeling and mapping.
Typically, geological information collected from Earth's subsurface is identified by its spatial location, specifically geographic (x, y) coordinates, i.e., longitude and latitude, and elevation or depth (z), usually relative to mean sea level. This allows subsurface data types to be categorized, utilized and marketed based on these identifiers.
A geologic basin may be comprised of hundreds of rock layers or strata (formations) deposited over geologic time. Thus, a characteristic attribute of a stratum is the age of deposition (T), which in a sense could be considered as a fourth dimension. A geologic time scale has been created to subdivide Earth's history into eras and periods based on the absolute age of rocks, fossils and sediments using radiometric dating, paleontology and other methods. Chronostratigraphy is then used to identify the age of rock strata in relation to time and relying on absolute age. Lithostratigraphy involves the correlating of key rock sequences to map continuous geologic formations within a particular area, such as a portion of a particular basin.
A method to obtain digital spatial data and a stratigraphic correlation or framework from well logs in a particular area or basin is described in U.S. Pat. No. 7,054,753, which is fully incorporated by reference herein.
When attempting to understand a single formation or a short geographic distance, e.g., within a common basin, lithostratigraphy may match chronostratigraphy fairly well. However, changes in the strata from other geologic forces, or the arrangement of the various strata layers over relatively large geographic distances cannot readily be accounted for using lithostratigraphic correlation. Chronostratigraphic correlation becomes very difficult, if not impossible in view of the limited lithostratigraphic data that are available, which are, at best, limited, disjointed and mainly comprised of numerous forms of analog data presented as well logs recorded over the past century. What is needed therefore is an overall chronostratigraphic framework within which geologic data can be inserted and categorized along with a time event such that the data may be queried and organized based on the age as well as spatial coordinates.